The feasibility of using layered-Functionally Graded Self Compacting Cement Composite (FGSCCC) for precast shield-tunnel segments, in harmony with present concrete industry sustainability trend, is presented herein. Limestone powder-type Self-Compacting Cement Composites (SCCC) either with silica fume (SiF) or with SiF and steel fibres (SF) were formulated for the watertight layer. While, SCCC with polypropylene fibres (PPF) or light weight aggregates and SF (LWA+SF) were used for the fire-resistant ones. Besides, a high strength SCCC (HS-SCCC) was considered for structural layers and monolithic samples. Layer composition influence and interlayer robustness on the structural element properties were evaluated. Experiments showed that the FGSCCCs are more effective than the HS-SCCC solutions in front of water, chloride, carbonation, fire or in terms of residual strength. Thanks to its precise spatial material arrangement, the effect of fire or the risk of steel reinforcement corrosion substantially decreases. The residual compressive strength, of FGSCCC specimens with LWA+SF layers, slightly decreases compared to that with PPF layers. Furthermore, they showed the increase of toughness of these specimens. Although none sharp failure at interface was observed, the results pointed out the necessity of considering other different effective parameters for validating the significance of casting process based on rheology.

This paper presents a method for determining material constants of hyperelastic material used for building the soft robotic actuators. Sixty testpieces were made of silicone rubber with a shore A hardness from 20 A to 45 A. Each of them was then subjected to the uniaxial tensile test to obtain the stress–strain relationship, which is a key factor to evaluate the compatibility of the common six forms of strain energy density function for hyperelastic material. The sum of square error was used to determine the most relevant constitutive models, which are Ogden third order, Polynomial second order, and Yeoh, as well as parameter values of the corresponding materials. To analyze the appropriateness of these models for computation, six pneumatic soft actuators were built from materials with different hardness and tested for various pressures. From the simulation and experimental results, the model Yeoh has yielded the highest accuracy. This outcome forms a firm basis for the determination of suitable material in the computation and simulation of the pneumatic soft actuator. Besides, the obtained experimental results in this paper could be included in the database of hyperelastic material with different hardness for further simulation in the related field.

Although the use of concrete and reinforced concrete for construction has been widespread, more studies are needed on marine structures exposed directly to corrosive environments to prolong their service life. This paper proposes a new type of shell precast concrete block for coastal structures, studying a beam consisting of 15mm High-Performance Glass Fiber-Reinforced Concrete (HPGFRC) at the bottom and 45mm Traditional Concrete (TC) for the rest of the structure. Steel bar reinforcements were placed at the bottom with a concrete cover of 25mm to avoid abrupt failure. The strength classes of HPGFRC and TC were 60MPa and 30MPa respectively. A reference beam consisting of TC only was also prepared for comparison. The four-point flexural bending test results showed that the first cracking strength of the proposed beam was 20% higher, as HPGFRC performed better on tension than TC. Additionally, HPGFRC's maximum strength was 25% greater than TC's. Furthermore, HPGFRC possessed more durable characteristics such as waterproof grade, abrasion resistance, and shrinkage than TC, promising to protect the reinforcement from the aggressive marine environment and corrosion, prolonging the service life of the structure.

Water quality directly influences human life. Drinking water contamination can result in severe health problems. This paper deals with the analysis of water specimens from submergence of material containing high sulfuric fly ash as base course material for road building. The specimens were obtained from real road testing. Results showed that for the material that used fly ash and chemical admixture, water quality was suitable for drinking in accordance with the standard parameters prescribed by the Vietnam Ministry of Health, while for the material that used the same fly ash without chemical admixture, the total arsenic content was eight times higher than that of the former. Thus, if one desires to utilize fly ash with high sulfur as base course material for road building, it needs to be used in combination with appropriate chemical admixture, so that it would not affect ground water quality.

This paper presents an improved generalized procedure for dealing with the stability of thin-walled beams under combined symmetric loads based on the energy method. The differential equations for the case of complex loading conditions were developed using an axis transformation matrix. The work caused by external loads was related to the work of internal forces to simplify the computational procedure. The thin-walled beam subjected to axial force [Formula: see text], bending moment [Formula: see text] at both ends, and concentrated load [Formula: see text] at midspan was studied. The case of a concentrated load [Formula: see text] replaced by a distributed load [Formula: see text] over partial beam length was also examined. The stability region boundary of the beam was derived by two approaches: one was to estimate an approximate angle of twist prior to determination of the deflection and the other was to do it in the reverse way. Numerical results reveal that the first approach yields less error than the second; however, the outcome obtained by the former was more cumbersome than the latter. Above all, both approaches provided feasible results and are useful for further applications dealing with the stability analysis of thin-walled beams.